The two leaders began their meeting by holding a joint prayer service at the St George Church in Istanbul.

The two ancient branches of Christianity - the Eastern and the Western rites - split nearly 1,000 years ago over disputes including papal authority.

In Istanbul, Benedict will also meet faith leaders and visit the city's famous Blue Mosque. He is also scheduled to lead Mass in a cathedral.

Istanbul was once Constantinople - the centre of the Byzantine empire, but now the largest city in a secular Turkish republic.

Pilgrimage

The service in Ephesus was the only open-air Mass Pope Benedict was to say in Turkey, for a congregation of some 500 Catholics brought to the shrine by special invitation.

The Pope was in Ephesus to visit a shrine to the Virgin Mary

The Pope visited the small stone house set in the lush green hillside where the Virgin Mary is thought to have spent her last days.

It is visited every year by tens of thousands of pilgrims.

He also honoured the memory of a Roman Catholic priest who was killed amid Muslim anger over the publication of caricatures of the Prophet Muhammad.

"Let us sing joyfully, even when we're tested by difficulties and dangers, as we have learned from the fine witness given by the Roman priest John Andrea Santoro, whom I am pleased to recall in this celebration," he said.

HAVE YOUR SAY

It's such a shame that the Pope's visit was overshadowed by protests before his arrival